Abstract : Scientific communities extensively exploit simulations to validate their theories. However, the relevance of the obtained results highly depends on the accuracy of the dataset they use. This statement is particularly true when considering human mobility traces, which tend to be highly unpredictable. In this paper, we therefore introduce \textsc{AntDroid}, a distributed platform for sensing the activities of mobile users. In particular, \textsc{AntDroid} offers to scientists a participative platform for helping them to easily setup and exploit mobile sensing experiments. Beyond the scientific contribution of this platform, the technical originality of \textsc{AntDroid} lies in its Cloud orientation, whose implementation is based on an extension of the SCA component model that complies with the REST architectural style. This modular infrastructure provides a scalable yet open environment, which can be configured and customized according to the scientist requirements. We validate this platform by sensing various activities of mobile participants using Android smartphones.